Math Problem Statement

given f(x)=-2x+3 and g(x)=1/2x-2 find x when f(g(x))=9

Solution

To find the value of xx when f(g(x))=9f(g(x)) = 9, follow these steps:

Given:

f(x)=2x+3f(x) = -2x + 3 g(x)=12x2g(x) = \frac{1}{2}x - 2

Step 1: Find f(g(x))f(g(x))

Substitute g(x)g(x) into f(x)f(x): f(g(x))=f(12x2)f(g(x)) = f\left(\frac{1}{2}x - 2\right) Now, replace xx in f(x)=2x+3f(x) = -2x + 3 with 12x2\frac{1}{2}x - 2: f(g(x))=2(12x2)+3f(g(x)) = -2\left(\frac{1}{2}x - 2\right) + 3 Distribute the 2-2: f(g(x))=212x+4+3f(g(x)) = -2 \cdot \frac{1}{2}x + 4 + 3 Simplify: f(g(x))=x+7f(g(x)) = -x + 7

Step 2: Set f(g(x))=9f(g(x)) = 9

x+7=9-x + 7 = 9

Step 3: Solve for xx

Subtract 7 from both sides: x=2-x = 2 Multiply by 1-1 to solve for xx: x=2x = -2

So, x=2x = -2.

Would you like further details or have any questions?

Here are 5 related questions to expand on this topic:

  1. What is g(f(x))g(f(x)) for the given functions?
  2. How would the solution change if f(g(x))=9f(g(x)) = -9?
  3. What is the inverse of f(x)f(x) and g(x)g(x)?
  4. How do the graphs of f(x)f(x) and g(x)g(x) look?
  5. Can you find f(x)=0f(x) = 0 for the given f(x)f(x)?

Tip: When solving equations involving function compositions, always carefully apply the functions step by step to avoid mistakes.

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Math Problem Analysis

Mathematical Concepts

Function Composition
Linear Functions

Formulas

Function composition formula
Equation solving techniques

Theorems

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Suitable Grade Level

Grades 9-12